Mitsubishi Electronics MDS-D-SPJ3 Engraver User Manual


 
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7 Selection
MITSUBISHI CNC
(a) Horizontal axis load torque
When operations [1] to [8] are for a horizontal axis, calculate so that the following torques are required in
each period.
Table 7-3 Load torques of horizontal axes
(b) Unbalance axis load torque
When operations [1] to [8] are for an unbalance axis, calculate so that the following torques are required in
each period. Note that the forward speed shall be an upward movement.
Table 7-4 Load torques of unbalance axes
Period Load torque calculation method Explanation
[1] (Amount of acceleration torque) + (Kinetic friction torque)
Normally the acceleration/deceleration time con-
stant is calculated so that this torque is 80% of the
maximum torque of the motor.
[2] (Kinetic friction torque)
[3] (Amount of deceleration torque) + (Kinetic friction torque)
The absolute value of the acceleration torque
amount is same as the one of the deceleration
torque amount. The signs for the amount of accel-
eration torque and amount of deceleration torque
are reversed.
[4] (Static friction torque)
Calculate so that the static friction torque is always
required during a stop.
[5] - (Amount of acceleration torque) - (Kinetic friction torque)
The signs are reversed with period <1> when the
kinetic friction does not change according to move-
ment direction.
[6] - (Kinetic friction torque)
The signs are reversed with period <2> when the
kinetic friction does not change according to move-
ment direction.
[7] - (Amount of deceleration torque) - (Kinetic friction torque)
The signs are reversed with period <3> when the
kinetic friction does not change according to move-
ment direction.
[8] - (Static friction torque)
Calculate so that the static friction torque is always
required during a stop.
Period Load torque calculation method Explanation
[1]
(Amount of acceleration torque) + (Kinetic friction torque) +
(Unbalance torque)
Normally the acceleration/deceleration time con-
stant is calculated so that this torque is 80% of the
maximum torque of the motor.
[2] (Kinetic friction torque) + (Unbalance torque)
[3]
(Amount of deceleration torque) + (Kinetic friction torque) +
(Unbalance torque)
The absolute value of the acceleration torque
amount is same as the one of the deceleration
torque amount. The signs for the amount of acceler-
ation torque and amount of deceleration torque are
reversed.
[4] (Static friction torque) + (Unbalance torque)
The holding torque during a stop becomes fairly
large. (Upward stop)
[5]
- (Amount of acceleration torque) - (Kinetic friction torque)
+ (Unbalance torque)
[6] - (Kinetic friction torque) + (Unbalance torque)
The generated torque may be in the reverse of the
movement direction, depending on the size of the
unbalance torque.
[7]
- (Amount of deceleration torque) - (Kinetic friction torque)
+ (Unbalance torque)
[8] - (Static friction torque) + (Unbalance torque)
The holding torque becomes smaller than the up-
ward stop. (Downward stop)
During a stop, the static friction torque may constantly be applied. The static friction torque and
unbalance torque may be applied during an unbalance axis upward stop, and the torque during a stop
may become extremely large. Therefore, caution is advised.
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